Woo-sik thinks ‘man’ should be ‘manly’ in every ways. What he’s talking about, with his friends at a bar just tells us how often and seriously we discriminate against others out there; sexual discrimination, racial discrimination, treating waitresses so bad, homophobia, etc. In the end, all of his friends left him behind and he came over to a stranger saying “you know what I mean, ’cause you a ‘man’!”